Package structure and manufacturing method thereof

ABSTRACT

A package structure includes a first redistribution structure, a chip, an insulation encapsulation and a protection layer. The first redistribution structure has a first surface and a second surface opposite to the first surface. The chip is disposed on the first surface of the first redistribution structure and has an active surface and a rear surface opposite to the active surface. The insulation encapsulation encapsulates the chip and the first surface of the first redistribution structure. The protection layer is directly disposed on the rear surface of the chip.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of U.S. provisional application Ser. No. 62/484,907, filed on Apr. 13, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to a package structure and a display, in particular, to a package structure having a protection layer.

2. Description of Related Art

With advancement of the technology, the electronic product has been designed to achieve being light, slim, short, and small, so as to develop products that are smaller in volume, lighter in weight, higher in integration, and more competitive in the market. As the products gradually shrinkage in volume, the risk of malfunction or failure of the electronic chip due to crack or warpage is increased accordingly. As such, how to miniature the package structure while maintaining the reliability and the functionality of the package, so as to lower the risk of failure of the final products, has become a challenge to those researchers in the field.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a package structure and a manufacturing method thereof, which can lower the risk of malfunction or failure of a package structure of the chip and enhance the reliability thereof.

The present invention provides a package structure including a first redistribution structure, a chip, an insulation encapsulation, a protection layer. The first redistribution structure has a first surface and a second surface opposite to the first surface. The chip is disposed on the first surface of the first redistribution structure and has an active surface and a rear surface opposite to the active surface. The insulation encapsulation encapsulates the chip and the first surface of the first redistribution structure. The protection layer is directly disposed on the rear surface of the chip.

The present invention provides a manufacturing method of a package structure. The method includes at least the following steps. A first carrier substrate is provided. A first redistribution structure having a first surface and a second surface opposite to the first surface is formed on the first carrier substrate. The first surface is attached to the first carrier substrate. A second carrier substrate attached to the second surface of the first redistribution structure is provided. The first redistribution structure is separated from the first carrier substrate. A chip is disposed onto the first surface of the first redistribution structure. The chip has an active surface and a rear surface opposite to the active surface. A protection layer is formed on the rear surface, and the active surface is adhered to the first surface of the first redistribution structure.

Base on the above, the protection layer is formed on the rear surface of the chip. Accordingly, the chip is strengthened to sufficiently alleviate the warpage issues during the manufacturing process of the package structure. Moreover, since the issues of the warpage of the chip are alleviated, the flip-chip bonding yield may be improved to avoid the non-joint issue. As result, the overall strength of the chip having the protection layer disposed thereon is enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1A to FIG. 1J are schematic cross-sectional view illustrating a manufacturing method of package structure according to an embodiment of the present invention.

FIG. 2A to FIG. 2D are schematic cross-sectional view illustrating a manufacturing method of the chip and the protection layer of the package structure according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a package structure according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a package structure according to another embodiment of the present invention.

FIG. 5A to FIG. 5C are a schematic views illustrating some exemplary embodiments of the semiconductor packages wherein the package structure of FIG. 1J is applied.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

FIG. 1A to FIG. 1J are schematic cross-sectional view illustrating a manufacturing method of package structure according to an embodiment of the present invention. Referring to FIG. 1A, a first carrier substrate 60 is provided. In the embodiment, the first carrier substrate 60 may be made of silicon, polymer or other suitable materials. A first release layer 70 is formed on the first carrier substrate 60 to enhance the adhesion between the first carrier substrate 60 and the other structures subsequently formed thereon, and to improve the rigidity of the overall package structure during the manufacturing process. The first release layer 70 is, for example, a light to heat conversion (LTHC) adhesive layer or other suitable adhesive layers.

Referring to FIG. 1B, a first redistribution structure 100 is formed on the first carrier substrate 60 and the first release layer 70. In the embodiment, the first redistribution structure 100 has a first surface 100 a and a second surface 100 b opposite to the first surface 100 a. The first redistribution structure 100 may include a plurality of dielectric layers and a plurality of conductive elements disposed therein. As illustrated in FIG. 1B, the first conductive elements 120 includes three trace layers 121, 122, 123, respectively disposed in the three dielectric layers 111, 112, 113. The first conductive elements 120 include a plurality of interconnect structures connecting the trace layers 121, 122, 123. A plurality of ball pads 126 formed on the second surface 100 b are included in the first conductive elements 120 and electrically connected to the trace layers 121, 122, 123 through the interconnect structures. For example, the trace layer 121 may be first formed on the first carrier substrate 60. Next, the dielectric layer 111 including a plurality of openings may be formed over the first carrier substrate 60 to cover the trace layer 121 and the openings of the dielectric layer 111 may expose at least a portion of the trace layer 121. Subsequently, the trace layer 122 may be formed in the openings and on the dielectric layer 111 and the trace layer 122 is electrically connected to the trace layer 121. The abovementioned steps may be performed multiple times to sequentially form the dielectric layer 112, the trace layer 123, the dielectric layer 113 and the ball pads 126.

As shown in FIG. 1B, the dielectric layer 113 exposes the trace layer 123 and the interconnect structures disposed thereon, such that the trace layer 123 may electrically connect to other trace layers or package structures through the interconnect structures. The patterned circuits may be formed from the trace layer 122 with a fine-pitch pattern located in the dielectric layer 112 to the trace layer 121 with a large pattern located on the first surface 100 a for obtaining a better fine line-and-space (L/S) RDL (redistribution layer) yield. In addition, the ball pads 126 may be made of copper, nickel, tin, gold, silver or a combination thereof.

Referring to FIG. 1C, a second carrier substrate 80 is attached to the second surface 100 b of the first redistribution structure 100. Moreover, a second release layer 90 is formed between the second carrier substrate 80 and the first redistribution structure 100. The ball pads 126 may be embedded within the second release layer 90. The first carrier substrate 60 is detached and separated from the first surface 100 a of the first redistribution structure 100 through the first release layer 70 following a direction pointed by the direction arrows in FIG. 1C.

Referring to FIG. 1D, after the first redistribution structure 100 is separated from the first carrier substrate 60, the first surface 100 a of the first redistribution structure 100 may have desired surface coplanarity for the subsequent flip-chip bonding processes. In the present embodiment, the surface of the trace layer 121 exposed on the first surface 100 a may be lower than that of the dielectric layer 111. A height level difference between the surface of the dielectric layer 111 and the surface of the trace layer 121 may be smaller than 3 μm. Moreover, a plurality of conductive pillars 200 is formed on the first surface 100 a of the first redistribution structure 100 and electrically connected to the trace layer 121. In the present embodiment, the conductive pillars 200 may be made of copper, nickel, tin, gold, silver or a combination thereof.

Referring to FIG. 1E, a chip 500 is disposed on the first surface 100 a of the first redistribution structure 100 through a flip-chip bonding process. However, it construes no limitation in the invention. The number of the chip 500 is not limited and may depend on circuit design. As illustrated in FIG. 1E, the conductive pillars 200 may surround the chip 500. The chip 500 has an active surface 520 and a rear surface 540 opposite to the active surface 520. A protection layer 600 may be directly formed on the rear surface 540 before the chip 500 is disposed on the first surface 100 a. The protection layer 600 can prevent the chip 500 from cracking during the flip-chip bonding process. In addition, with the aid of the protection layer 600, especially for a large-sized chip, the issue of chip warpage may be eliminated and the flip-chip bonding yield may be improved to avoid the non joint issue, thereby enhancing the overall strength of the subsequently formed package structure 10 (as shown in FIG. 1J). A Capillary Underfill (CUF) 300 is formed between the active surface 520 of the chip 500 and the first surface 100 a of the first redistribution structure 100 and surrounds a lateral side 530 of the chip 500. The protection layer 600 on the rear surface 540 of the chip 500 may prevent the CUF 300 from overflowing to the rear surface 540. The CUF 300 may be formed using insulating materials, such as epoxy or other suitable resins. Furthermore, a plurality of bumps 550 and pads 560 are formed between the active surface 520 and the first surface 100 a of the first redistribution structure 100 as the interconnection structures for electrically connecting the chip 500 to the conductive elements 120 of the first redistribution structure 100.

Referring to FIG. 1F, the chip 500, the protection layer 600, and the conductive pillars 200 are encapsulated by an insulation encapsulation 700. As shown in FIG. 1F, the insulation encapsulation 700 is formed over the chip 500, the protection layer 600, and the conductive pillars 200, such that the insulation encapsulation 700 completely covers all conductive pillars 200, the chip 500, and the protection layer 600. The insulation encapsulation 700 may include molding compounds disposed on the first redistribution structure 100 using a molding process. As illustrated in FIG. 1F, the insulation encapsulation 700 may have a thickness t1, which is larger than the height of the conductive pillars 200.

Referring to FIG. 1G, the thickness of the insulation encapsulation 700 is thinned from thickness t1 to thickness t2 to expose top surfaces of the conductive pillars 200 for subsequent processes of forming, for example, another redistribution structure thereon. The insulation encapsulation 700 may still be covering the protection layer 600 after the thinning process. After the thinning process, a surface roughness of the insulation encapsulation 700 and the conductive pillars 200 may be enhanced, thereby increasing an adhesive property with layers subsequently formed thereon. The thinning process may be performed using mechanical grinding, Chemical-Mechanical Polishing (CMP), etching, or other suitable methods. The etching process for the conductive pillars 200 may include anisotropic etching or isotropic etching.

Referring to FIG. 1H, a second redistribution structure 400 is formed above the insulation encapsulation 700. The second redistribution structure 400 may include at least a dielectric layer and at least a conductive element. As shown in FIG. 1H, the second redistribution structure 400 includes the second conductive elements 420. The second conductive elements may include trace layers 422, 423, respectively disposed in the dielectric layers 412, 413. In addition, the trace layers 422, 423 are electrically connected to the conductive pillars 200.

Referring to 1I and 1J, the second carrier substrate 80 is detached from the second surface 100 b of the first redistribution structure 100 through the release layer 90 to form a package structure 10 as shown in FIG. 1J.

FIG. 2A to FIG. 2D are schematic cross-sectional view illustrating a manufacturing method of the chip and the protection layer according to an embodiment of the present invention. Referring to FIG. 2A, a wafer 500′ has an active surface 520′ and a rear surface 540′ opposite to the active surface 520′ is provided. The active surface 520′ have a plurality of the bumps 550 and pads 560 formed thereon. Referring to FIG. 2B, the protection layer 600 is formed on the rear surface 540′. Referring to FIG. 2C, a singulation process is performed on the wafer 500′ to form a plurality of chips 500 as illustrated in FIG. 2C and FIG. 2D. The singulation process includes, for example, cutting with rotating blade or laser beam.

In the embodiment, a coefficient of thermal expansion (CTE) of the protection layer 600 is smaller than polyimide but larger than molding compound and silicon materials. For example, the CTE of the protection layer 600 ranges between 5 ppm/° C. and 40 ppm/° C. Accordingly, the protection layer 600 can reduce the risk of chip cracking or chipping during the sawing process of the wafer 500′. In addition, the protection layer 600 can be used as a buffer layer to reduce the chip 500 warpage and enhance the flip-chip bonding process yield to avoid non-joint risk, especially for a large-sized chip. Specifically, as the issues of the warpage of the chip 500 is alleviated, the chip 500 may be bonded to the trace layer 121 of the first redistribution structure 100 with fine-pitch line and space patterns by the aid of the alignment processes.

FIG. 3 is a cross-sectional view illustrating a package structure according to another embodiment of the present invention. The structure of the package structure 20 is similar to the package structure 10 in FIG. 1J. Thus, the identical components will be denoted with the same numerals and not repeated herein. The difference between the package structure 20 and the package structure 10 is that the insulation encapsulation 700 may be further thinned to remove the insulation encapsulation 700 disposed above the protection layer 600 to expose the protection layer 600. Accordingly, the top surface of the protection layer 600 may be coplanar with the top surface of the insulation encapsulation 700 and the top surfaces of the conductive pillars. Therefore, the second redistribution structure 400 can be directly in contact with the protection layer 600. In this embodiment, the protection layer 600 may serve as a buffer layer to avoid delamination between the second redistribution structure 400 and the chip 500 during the manufacturing process of the package structure 20.

In the present embodiment, the protection layer 600 may be made of materials similar to the insulation encapsulation 700, such as molding compound. Therefore, the protection layer 600 and the insulation encapsulation 700 may have similar properties. As such, the life time of the mold grinding wheel applying in the thinning/grinding process of the insulation encapsulation 700 and the protection layer 600 may be elongated. Furthermore, the protection layer 600 may have good thermal conductivity, which ranges between 2 W/m-k and 5 W/m-k, to enhance the thermal dissipation performance of the package structure 20.

FIG. 4 is a cross-sectional view illustrating a package structure according to another embodiment of the present invention. The structure of the package structure 30 is similar to the package structure 10 in FIG. 1J. Thus, the identical components will be denoted with the same numerals and not repeated herein. The difference between the package structure 30 and the package structure 10 is that a Molded Underfill (MUF) can be applied to replace the CUF 300. For example, the insulation encapsulation 700 may be a molding compound, sometimes called the MUF. The MUF may encapsulate the chip 500 and fill the gap between the chip 500 and the first redistribution structure 100, thereby improving the reliability of the package structure 30. Different underfills may be utilized according to the practical needs of the different package structures.

FIG. 5A to FIG. 5C are schematic views illustrating some exemplary embodiments of the semiconductor packages wherein the package structure 10 of FIG. 1J is applied. Referring to FIG. 5A, a stacking structure 800 may be formed above the package structure 10. A plurality of bumps 127 may be disposed on the bottom surface of the package structure 10 for bonding the package structure 10 on a circuit substrate or an interposer. In the embodiment, a plurality of the pads 814 may be formed on the surface of each chip 810 of the stacking chip structure 800. The pads 814 on the surfaces of the different chips 810 may be mutually bonded and electrically connected through a plurality of bumps 812 and wires 816. Each chip 810 of the stacking chip structure 800 may be also electrically connected and bonded to the package structure 10 and the chip 500 through the bumps 812 and the wires 816. As illustrated in FIG. 5A, an electromagnetic interference (EMI) shielding structure 50 may be disposed to surround and protect the package structure 10 and the stacking chip structure 800.

Referring to FIG. 5B, a plurality of fan-out structures 900 and a plurality of passive components 950, such as capacitors, inductors or antennas, may also be disposed above the package structure 10.

Referring to FIG. 5C, a plurality of wafer level chip scale package (WLCSP) structures 1000 and the passive components 950 may be disposed above the package structure 10. Accordingly, as illustrated in FIG. 5A, FIG. 5B and FIG. 5C, the configurations of the package structure 10 can be adjusted based on the practical needs of different functions or different kinds of applications.

In light of the foregoing, the package structure may include the first redistribution structure, the second redistribution structure and the chip. The second redistribution structure is disposed above the first redistribution structure. The chip is disposed and encapsulated between the first redistribution structure and the second redistribution structure and has an active surface and a rear surface opposite to each other. In addition, the package structure includes a package layer disposed on the rear surface of the chip.

In the manufacturing process of the package structure, the protection layer can prevent the chip from cracking or chipping during the wafer sawing process. In addition, as the chip is flip-chip bonded to the first redistribution structure, the protection layer can alleviate the issues of chip cracking and chip warpage, and the flip-chip bonding yield may be improved to avoid the non-joint issue, thereby enhancing the overall strength of the package structure.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

What is claimed is:
 1. A package structure comprising: a first redistribution structure having a first surface and a second surface opposite to the first surface; a chip, disposed on the first surface of the first redistribution structure and having an active surface and a rear surface opposite to the active surface; an insulation encapsulation, encapsulating the chip and the first surface of the first redistribution structure; and a protection layer, directly disposed on the rear surface of the chip.
 2. The package structure according to claim 1, wherein the first redistribution structure comprises at least one dielectric layer and a plurality of first conductive elements disposed in the at least one dielectric layer, and the chip is electrically connected to the first conductive elements exposed on the first surface.
 3. The package structure according to claim 2, further comprising a plurality of bumps, disposed between the active surface and the first surface of the first redistribution structure and electrically connected to the first conductive elements respectively.
 4. The package structure according to claim 3, wherein the surfaces of the bumps facing the first surface are substantially coplanar with a surface of the insulation encapsulation.
 5. The package structure according to claim 1, further comprising a second redistribution structure, disposed above the rear surface of the chip, the protection layer, and the insulation encapsulation.
 6. The package structure according to claim 5, further comprising a plurality of conductive pillars, surrounding the chip and disposed between the first redistribution structure and the second redistribution structure.
 7. The package structure according to claim 6, wherein the second redistribution structure comprises at least one dielectric layer and a plurality of second conductive elements disposed in the at least one dielectric layer, and the chip is electrically connected to the second conductive elements through the first redistribution structure and the conductive pillars.
 8. The package structure according to claim 1, further comprising an underfill, disposed between the first surface of the first redistribution structure and the active surface of the chip.
 9. The package structure according to claim 1, wherein a thickness of the protection layer ranges between 5 μm and 30 μm.
 10. The package structure according to claim 1, wherein the chip is electrically connected to the first redistribution structure through a flip-chip bonding process.
 11. A manufacturing method of a package structure, comprising: providing a first carrier substrate; forming a first redistribution structure having a first surface and a second surface opposite to the first surface on the first carrier substrate, wherein the first surface is attached to the first carrier substrate; providing a second carrier substrate attached to the second surface of the first redistribution structure; separating the first redistribution structure from the first carrier substrate; and disposing a chip on the first surface of the first redistribution structure, wherein the chip has an active surface and a rear surface opposite to the active surface, a protection layer is directly formed on the rear surface, and the active surface of the chip is adhered to the first surface of the first redistribution structure.
 12. The method according to claim 11, further comprising forming a first release layer between the first carrier substrate and the first redistribution structure.
 13. The method according to claim 11, further comprising forming a second release layer between the second carrier substrate and the second surface of the first redistribution structure for separating the second carrier substrate from the first redistribution structure.
 14. The method according to claim 11, wherein the step of forming the first redistribution structure further comprises forming at least one dielectric layer and a plurality of first conductive elements, and the chip is electrically connected to the first conductive elements.
 15. The method according to claim 14, further comprising forming a plurality of conductive pillars on the first surface of the first redistribution structure, wherein the conductive pillars surround the chip.
 16. The method according to claim 15, further comprising encapsulating the chip, the protection layer, and the conductive pillars by utilizing an insulation encapsulation.
 17. The method according to claim 16, wherein the step of encapsulating the chip, the protection layer and the conductive pillars comprises: disposing the insulation encapsulation over the chip, the protection layer, and the conductive pillars; and reducing a thickness of the insulation encapsulation to expose top surfaces of the conductive pillars.
 18. The method according to claim 17, further comprising forming a second redistribution structure above the insulation encapsulation.
 19. The method according to claim 18, wherein the step of forming the second redistribution structure comprises forming at least one dielectric layer and a plurality of second conductive elements, and the conductive pillars are electrically connected between the first conductive elements and the second conductive elements respectively.
 20. The method according to claim 11, wherein the step of disposing the chip on the first surface of the first redistribution structure comprises forming a plurality of bumps between the active surface of the chip and the first surface of the first redistribution structure. 